A variety of rotational devices are dependent upon load supporting bearings for operation. Because traditional bearings include components such as ball bearings, that are almost constantly in motion during device operation, heat caused by friction can build very quickly within the bearing. In addition, the bearing surfaces wear over time, which can further increase heat generation and friction losses. Eventually, almost all bearings fail due to excessive wear and the detrimental effects of heat on the components and lubricants. Because it is desirable to operate most rotational devices at or near their highest rpm level in order to optimize the amount of work produced, it should be appreciated that a bearing exposed to reduced amounts of friction would allow these devices to operate closer to their optimum levels while reducing the likelihood of bearing failure.
In one specific example, turbine engines necessarily include rotating elements that are interconnected to stationary elements via bearings. Because the turbine and bearings are often subjected to relatively high rotation rates and high temperatures, various components must often be constructed from exotic materials, such as ceramics and/or expensive temperature resistant metallic alloys. Because engine efficiency generally increases with both speed and temperature, engineers are constantly seeking ways to operate turbines even faster and at higher temperatures. However, the limitations of available materials place constraints in this area. One response to these constraints have been efforts to introduce cooling circuits into a turbine so that it can be operated at higher temperatures and/or utilize less exotic metallic alloys. However, in order to introduce a cooling fluid circuit into the turbine, there must necessarily be fluid seals that often have a great deal of difficulty withstanding the relatively hot hostile environment within a turbine. Thus, there remain significant problems to overcome in efforts to improve turbine engine efficiency without necessarily seeking ever more exotic and expensive materials.
The present invention is directed to overcoming one or more of the problems set forth above.